Analyzing Heavy Metal Pollution with the Induction Electromagnetic Method and the High-density Electrical Method in Urban Land

The electromagnetic method and the high-density electrical method were applied to the investigation of soil environmental of urban polluted land. A typical heavy metal-contaminated site in South China was taken as the research object. The induction electromagnetic method was used to preliminarily screen and describe the contaminated areas in two dimensions. The high-density resistivity method was used to further detect the pollution depth characteristics and vertical pollution range. There were many abnormal areas with low resistance less than 8 Ω·m (suspected heavy metal pollution area) in the soil layer of 0~8.0 m and 3.5~10.5 m depth in the waste dumping area and the downstream area of sewage treatment tanks. The low resistance anomaly areas were serious polluted by heavy metals such as As and Pb, and the maximum contents were 1 170.00 mg/kg and 2 700.00 mg/kg respectively. The results show that it is feasible to detect the heavy metal pollution in the polluted land with the combination of the induction electromagnetic method and the high-density electrical method. They can be used to preliminarily characterize the spatial distribution of heavy metal pollutants and then accurately guide the subsequent drilling location and sampling to provide scientific basis for the accurate investigation of soil pollution and remediation of contaminated sites.